Spinning of artificial filaments



Patented May 8, 1934 UNITED STATES PATENT ,OFFICE Whitehead, Cumberland, Md.,

assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application November 10, 1928, Serial No. 318,583

2 Claims.

This invention relates to the manufacture of films or filaments, such as artificial yarns, fibres, bristles, straw, ribbons and the like, from solutions containing organic derivatives of cellulose.

5 An object of our invention is to prepare filaments or films containing organic derivatives of cellulose that are tougher and more pliable than those heretofore made.

Another object of our invention is to form films or filaments containing organic derivatives of cellulose from solution containing a non solvent or precipitant for the organic derivatives of cellulose.

Another object of our invention is to form films or filaments containing organic derivatives of cellulose that become delustred readily. Other objects of our invention will appear from the following detailed description.

Artificial filaments containing organic deriva- 2 tives of cellulose have been prepared formerly by extrusion of solutions of the derivatives of cellulose in a volatile solvent through the orifices of a spinnerette into an evaporative atmosphere. Yarns made from such filaments are not as tough and pliable as may be desired, and therefore the amount of twist that may be imparted to them, or the closeness with which such yarns may be knitted, is limited, since if a predetermined limit is exceeded, the same tend to break or become materially weakened. Moreover such prior yarns or fabrics made from such yarns, become delustred in dyeing or scouring baths only at temperatures approaching that of boiling water, unless other delustring agents have been employedin the bath. We have found that if substances that are non-solvents or precipitants for the organic derivatives of cellulose are added to the spinning solution containing the same, filaments may be formed that are tougher and more pliable, and

4 also in some instances more readily delustred, than those made by the prior processes. Yarns made from such filaments, among other desirable properties, may have a much higher twist safely imparted thereto, they may be safely knitted 5 closely on a circular knitting machine and may, in some instances, be delustred in dyeing or scouring baths, at much lower temperatures than yarns made by the prior processes.

When hosiery and similar products are produced from artificial fibres, it is generally found that such products are too transparent and glossy for the uses for which they are intended. Normal delustering treatments upon normal yarns produced from cellulose esters and ethers, whilst giving a desirable opaque finish and subdued lustre to the product, causing a certain amount of distortion in the filaments and the yarn generally of the product, which distortion is detrimental to the appearance of these products. In the process of our invention, however, delustering and rendering opaque of the fibres by normal treatments or merely obtaining the delustering action by normal dye-bath treatments, as has been specified, does not bring about distortion of filaments and yarns and the finished articles have a desirable uniform and smooth appearance.

We have also found that yarns or filaments prepared in accordance with the present invention which have been relustered from the delustered state do not deluster so readily as they did originally as, for instance, at temperatures of 85 C. or thereabouts. This is true regardless of the particular method of relustering employed, for example, by treating with restricted solvents such as dichlor ethylene or with a solvent restricted with a non solvent such as acetic acid, acetone, etc. restricted with water, or by immersing the yarn or fabric made therefrom in an atmosphere of steam and then hot calendering the same or by the heavy adsorption of a solvent vapor or vapors.

In accordance with our invention, we prepare filaments or films from solutions containing organic der vatives of cellulose in a suitable solvent, in which solution there has been incorporated, either by solution or emulsification, a substance that is a non solvent or a precipitant for the organic derivatives of cellulose. The solution so formed, preferably after thorough mixing to obtain uniformity, may be filtered and then extruded through orifices of required size of a spinnerette either into a drying or evaporative atmosphere, as in dry spinning, or into a precipitating bath containing liquid such as water, kerosene, etc., as in wet spinning.

The filaments that may be formed by our invention may be the fine filaments having a denier of say 1 to 10 such as used for making yarns, or they may be much heavier having a denier of say 50 to 2000 denier to be used as artificial bristles for making brushes or for making artificial furs, etc. Our invention may also be advantageously employed for making tough and pliable films for photographic purposes or other purposes, for making plastics, etc., where pliability is required.

Any suitable organic derivative of cellulose may be used in our invention. These may be organic esters of cellulose such as cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate, or cellulose ethers such as ethyl cellulose, methyl cellulose and benzyl cellulose.

Any suitable solvent may be employed for making the solution of the organic derivatives of cellulose. Examples of such solvents are ace tone, acetone and ethyl or methyl alcohol, chloroform, ethylene dichloride, ethylene dichloride and ethyl or methyl alcohol, methylene chloride and ethyl or methyl alcohol, etc.

A large variety of non solvents or precipitants for organic derivatives of cellulose may be added to the solution of the same in accordance with our invention. These may be fatty acids such as stearic or oleic acids; waxes of various kinds; glycerides of fatty acids such as olein or stearin; petroleum hydrocarbons such as gasoline, kerosene, mineral lubricating oils, petrolatum or petroleum jelly, or paraffin wax; aromatic hydrocarbons such as benzene, toluene or xylene, etc. Mixtures of two or more of these non solvents or precipitants may be employed, and these may or may not be miscible with each other. Among other substances that may be employed are materials which when added in comparatively small quantities to solutions of the organic derivatives of cellulose do not cause precipitation of the same but which do so in large quantities. Examples of such substances are ethyl alcohol, methyl alcohol, water or polyhydric alcohols like glycerine or ethylene glycol. These substances should be employed in sufiicient quantities to cause at least incipient precipitation of the cellulose derivatives from the solution after it leaves the spinning jet.

When solid non solvents or precipitants are used, such as wax or parafiin, it is advisable either to mix the same with the solution of the derivative of cellulose at a temperature high enough to melt such solid; or else first to dissolve the solid in a small quantity of a solvent for the same, such as benzene, and add the solution so formed to the solution of the organic derivative of cellulose. The solution of the wax or paraflin should preferably be added slowly to permit the wax, which precipitates from its solution in the solvent employed for dissolving the organic derivative of cellulose, to become thoroughly disseminated or emulsified in colloidal form if necessary in the solution of the organic derivative of cellulose.

While we have found that the addition of even small quantities of fatty acids, waxes, petroleum hydrocarbons or aromatic hydrocarbons to the spinning solution improves the properties of the filaments formed, we find that the maximum benefit is derived when amounts of such substances equal to 2.5 to 10% or more of the weight of the derivative of cellulose present are added to the spinning solution.

The lustre of the films, filaments or yarns produced by our method may be readily subdued in some instances depending upon the amount and nature of the non solvent or precipitant added to the spinning solution. Thus, if 10% of kero- Filaments, yarns or films formed by our invention are tough and pliable, which is surprising since this would not be expected in theory. Thus, yarns made from our filaments may have a twist imparted thereto having 30 or 40% more turns per unit length than may the prior yarns, without reaching the weakening point. Yarns formed by our invention may be knitted 30% or more closer than yarns made by the prior process; that is, a circular knitted or warp knitted fabric may be formed having 30% more wales, courses or stitches than fabrics made from prior yarns. Yarns or bristles made by our process may be formed into stronger knots, while artificial straws or ribbons or the like made by our process have improved plaiting qualities and may be subjected to considerably more severe proc essing.

In those cases where a non solvent or precipitant is added to the spinning solution that is non volatile and insoluble in water such as oils, fats, etc., they might not always be entirely removed from the yarns or fabrics by the ordinary scouring method. Despite this fact, such yarns or fabrics may be subjected to such treatments as saponification, dyeing with vat dyes, basic dyes, or water insoluble dyes dispersed in colloidal solution, by normal methods with normal results.

In those cases where volatile non solvents or precipitants such as kerosene, gasoline, etc., are employed, practically all of such substances that remain after spinning is evaporated off from the yarn within a few days. The presence of these materials in the yarn does not adversely affect textile operations or dyeing, while even after these solvents are evaporated, the yarn has the desirable properties above described.

In order further to illustrate our invention but without limiting the scope thereof, the following specific examples are given.

Example I An acetone soluble cellulose acetate, containing approximately 54% of combined acetic acid, is dissolved in a solvent mixture consisting of 95 parts of acetone and 5 parts of water by weight. One part by weight of cellulose acetate is dissolved in 3 parts by weight of the solvent. To the solution thus formed petroleum jelly in amounts equal to about 10% of the weight of the cellulose acetate present is added, and the whole thoroughly mixed and the petroleum jelly emulsified in the spinning solution. This mixture is then filtered and is then spun through an orifice either into a drying atmosphere or into a precipitating bath by known methods. The petroleum jelly remains in the finished yarn.

As a variation of this process the petroleum jelly may be replaced by olive oil to the extent of 5% of the weight of the cellulose acetate employed.

Example II A cellulose acetate having an acetyl value of approximately 62.5% is dissolved in a solvent mixture containing 85 parts of ethylene dichloride and 15 parts of methyl alcohol by weight. The solution is formed so that it has a concentration of 22.5% of cellulose acetate. To this solution, xylene to the extent of 8% of the weight of the cellulose acetate employed is added, and after thorough mixing and filtration is spun in any known manner either by wet or dry spinning methods. The xylene, if not entirely removed in the spinning process may evaporate off from the yarn Within a few days.

Example III An acetone soluble cellulose acetate having an acetyl value of approximately 54% is dissolved in chemically pure acetone to form a solution having a concentration of about 25% by weight of cellulose acetate. To this solution is added kerosene in amounts equal to 8% of the weight of the cellulose acetate. The solution is then spun in any known manner.

If desired, the kerosene may be replaced by gasoline, in which case an amount equal to 5% of the weight of the cellulose acetate may be used.

Example IV As an example of a process in which two or more non solvents or precipitants are employed in a spinning solution, the following is given. A cellulose acetate of 55.5% acetyl value is dissolved in chemically pure acetone to form a solution having a concentration of 26% of cellulose acetate. To this is added water in amounts equal to 20% of the cellulose acetate present and kerosene in amounts equal to 5% of the cellulose acetate present. After thorough mixing and filtration the same may be spun in any of the usual manners.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention what we claim and desire to secure by Letters Patent is:

1. Method of forming artificial filaments comprising dissolving acetone soluble cellulose acetate in a solvent, adding kerosene thereto and extruding the same through an orifice into an evaporative medium that causes the formation of filaments.

2. The method of forming artificial filaments comprising dissolving acetone soluble cellulose acetate in a solvent, adding a substance selected from the group consisting of kerosene and gasoline thereto and extruding the same through an orifice into an evaporative medium that causes the formation of filaments.

CAMILLE DREYFUS. WILLIAM WHITEHEAD. 

